Measuring the concentration of substances, particularly in the presence of other substances, is important in many fields. This is especially true in medical testing and diagnosis. For example, the measurement of glucose in body fluids, such as blood, is crucial to the effective treatment of diabetes. A blood glucose meter is used as a diagnostic device to measure blood glucose levels of patients suffering from diabetes. Blood glucose meters use a test strip that receives a blood sample of the patient. The test strip has electrical contacts on the strip that are electrically contacted when the test strip is inserted into the meter. The meter determines a blood glucose level by measuring currents passed through the electrical contacts of the strip, and provides for readout of the glucose level.
A sample-receiving portion of the testing apparatus typically controls the geometry of the blood sample. In the case of blood glucose meters, for example, the blood sample is typically placed onto or into a disposable test strip that is inserted into a test meter. In the case of electrochemical test meters, electrical signals must be transferred between the meter and the test strip and vice versa. Known meters receive the test strip in an insertion direction that also engages the electrical strip conductors of the test strip with the electrical contacts of the meter. As the test strip is loaded by the user, the insertion motion is used to drive the electrical contacts of the test strip into engagement with the contacts of the meter.
Test system designers desire to minimize the size of the sample required for accurate measurement in order to improve the user experience. The resulting test sensor and test strip miniaturization has resulted in the use of thin film test strip patterns comprised of noble metals deposited on plastic substrates, such as by plating and subsequent laser ablation, to form the electrodes and associated connector contact pads of the test strip. Test strips can include for example of a thin film of a polymeric material such as a polyester which is coated such as by sputtering pure gold to a 50 nm thickness. Because the gold film is so thin and does not adhere well to the plastic film, the gold film coatings are prone to scratching by current commercially available connectors. Therefore, reducing abrasion between the test strip contact pad and meter connector contact wire is especially important in biosensor designs. Repeat insertions of the test strip (two to four times) can render these thin film-coated biosensors useless. Even the first-time insertion of the test strip into the test meter may cause some removal of these thin film coatings by the test meter connector. The result is a less reliable connection between the contact pad on a test strip and the connector contact wire in the test meter.
Present connectors used in blood glucose meters can include both a long extending first beam portion to provide flexibility and a second oppositely directed bent wire form at the contact end with the test strip. The bent wire form imparts residual stresses in the connector. The bent wire form also provides poor dimensional control at the clearance point where the test strip contacts the connector. The bent wire form is therefore commonly positioned closer to the test strip than necessary, requiring a greater force to displace and thereby also causing greater potential for removal of the gold layer.
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.